Explosion-proof sliding gate valves are used in pipelines and plants which conduct potentially explosive gases and/or dusts. The pipeline or plant is equipped with pressure sensors and/or flame sensors which detect an explosion and activate one or more gas generators which contain an explosive or gas charge. As a result of the generated pressure, the sliding gate valve is closed and so effectively prevents the propagation of flames and pressure waves. Also known are explosion-proof sliding gate valves which are operated by means of a pneumatic, hydraulic and/or mechanical accumulator device, for example a compression spring.
In this case, the sealing plate is first of all accelerated powerfully and then, upon reaching the closed position, is braked. Consequently, the sealing plate has to be of a robust construction and must not be damaged especially when reaching the closed position since otherwise the sealing properties are not sufficient to block flames and pressure waves.
In order to damp the sealing plate when reacting the closed position use is made of oil piston brakes which also prevent the recoil of the sealing plate after reaching the closed position. After an activation of the sliding gate valve, these do not have to be replaced or serviced but are very cost intensive in their acquisition. Alternatively, it is known—e.g. from U.S. Pat. No. 3,980,094 or U.S. Pat. No. 6,131,534—to arrange a damping element in an impact region of the sealing plate. The damping element is formed from a plastically deformable material and is deformed upon impact of the sealing plate. After an activation of the sliding gate valve, the damping element has to be replaced, which is often associated with appreciable cost.